Evaluation of the hydrodynamic pressure of cavitation impacts from stress–strain analysis and geometry of individual pits

The present paper focuses on the development of an inverse procedure able to infer the hydrodynamic pressure distribution acting on the material surface and responsible for the creation of the cavitation pit based on the stress in a cavitation pit and its geometrical features. To achieve this goal, experimental pitting and nanoindentation measurement techniques were used together with a model of pit formation based on a Gaussian distribution of the hydrodynamic impact pressure pulse. The pitting tests were performed at four different operating pressures on aluminum alloy samples and the geometrical characteristics of the pits were measured. Then the strain, stress, and load in a cavitation pit were quantified by coupling the pitting test analysis with the material information obtained via the indentation tests. Finally, a Gaussian distribution of the hydrodynamic impact pressure on the material surface has been hypothesized and the peak of this distribution as well as its width have been inferred. This procedure, allowing the evaluation of the hydrodynamic impact pressure and load responsible for the material erosion and the deduction of insightful information on the flow aggressiveness at different operating conditions, could certainly represent a significant step in developing a technique able to evaluate the cavitation intensity from pitting tests.